Marking ink and method of using the same

ABSTRACT

This invention relates to a new ink and a method for applying the ink to a surface, in particular to gelatin layers of photographic materials. The ink is comprised of a hydrophilic dye and a watersoluble, non-drying low molecular weight solvent which is liquid at room temperature.

United States Patent [191 Vetter et a1.

[11] 3,816,144 June 11, 1974 1 MARKING INK AND METHOD OF USING THE SAME [75] Inventors: Hans Vetter, Cologne; Giinter Meinhardt, Leverkusen, both of Germany [73] Assignee: Agfa-Geva'ert Aktiengesellschaft,

Leverkusen, Germany [22] Filed: July 7, 1971 [21] Appl. No.: 160,515

[30] Foreign Application Priority Data Y July 11, 1970 Germany 2034481 [52] US. Cl 106/22, 106/20, 106/32, 106/285, 106/311,117/112, 117/141 [51] Int. Cl C09d 11/00 [58] Field of Search 106/19-23,

[5 6] References Cited I UNITED STATES PATENTS 2,146,873 2/1939 Wilmanns 106/210 2,556,902 6/1951 Chambers et al 106/24 X 2,684,909 7/1954 Leekley et a1. 106/24 2,686,732 8/1954 Montgomery et al... 106/154 R 3,486,912 Dyson 106/22 FOREIGN PATENTS OR APPLICATIONS 502.026 3/1939 Great Britain 96/78 862,085 3/1961 Great Britain 1. 96/78 Primary Examiner-Joseph L. Schofer Attorney, Agent, or Firm-Connolly and Hutz 57 1 ABSTRACT 5 Claims, No Drawings 1 MARKING INK AND METHOD OF USING THE SAME cloths impregnated with these dye solutions. The.

stamping or printing inks used for this purpose generally consist of dyes dissolved or dispersed either in mixtures of glycerol and water or in oleic acid or other veg etable oils such as castor oil, rape seed oil and the like or mineral oils. Stamping-and printing inks of this type have been described, for example, in Ullmanns Enzyklopaedie der technischen Chemie, 3rd Edition 1964, Volume 15, page 353 et seq.

The known marking inks are, however, not suitable for marking gelatin layers with marks which cannot be wiped off and'which are resistant to photographic processing baths. In most of the photographic copying materials used nowadays, paper is used as'the support for the light sensitive layers but for various reasons paper is nowadays increasingly being covered with synthetic resin surfaces or completely replaced by synthetic resin foils. When such synthetic resin materials are used as supports, it is found that the photographic layers, which preferably contain gelatin as binder, have an increased tendency to curl when the photographic layers dry. This tendency to curl can be counteracted by applying another gelatin layer on the rear surface of these materials. a

It is an object of the invention to find a process which enables marks which are resistant to various photographic baths and cannot be wiped off to be applied to gelatin layers of photographic materials.

A marking ink has now been found which is suitable for marking absorbing surfaces, in particular gelatin layers and which comprises a mixture of a dye which is non-diffusing in gelatin in a water-soluble and nondrying low molecular weight solvent which is liquid at room temperature.

This invention therefore relates to a process for marking absorbing surfaces, in particular gelatin layers of photographic materials, which is characterised in that a mixture of a hydrophile dye ,which is nondiffusing in gelatin in water-soluble, non-drying, low molecular weight solvent which is liquid at room temperature is applied in the form of the required patterns or symbols.

In the context of this invention, non-drying solvents are understood to mean solvents which" are so difficultly volatile that a woven ribbon impregnated with such solvents will not dry out but will remain able to transfer the solvent partially to an absorbing surface even when kept uncovered under normal conditions for 30 days. This property is particularly important because the marking ink is primarily intended for use in typing ribbons or printing cloths which should, of course, preserve their capacity to color the surface to which they are applied even when they have been stored or kept in use for considerable lengths of time and which therefore must not dry up. The dye solutions must be liquid and sufficiently fluid to ensure that por- 'tions of the ribbon which are frequently used will not become depleted of dye solution. Therefore, only low molecular weight solvents can be used having a molecular weight not higher than 300.

The solvents used are preferably primary or secondary hydroxyalkyl formamides of the following general formula I:

wherein R represents a straight chain or branched chain alkylene radical with up to six carbon atoms; R represents a hydrogen atom, a straight chain or branched chain alkyl radical'with up to four carbon atoms, a straight chain or branched chain hydroxyalkyl radical with up to six carbon atoms or a straight chain or branched chain formylaminoalkyl radical with up to six carbon atoms.

The following compounds are especially suitable:

The preparation of Compound 1 has been described in J. Am. Chem. Soc. 57, (1935), page 1080. The other compounds are prepared in an analogous manner.

The dyes used may be any dyes in particular hydrophilic dyes which are non-diffusing in gelatin and soluble in any one of these solvents defined as above or in mixtures of these solvents, if desired, with the addition of water, preferably those azo dyes which also may be used for the silver dye bleaching process. Such dyes have been described, for example, in German Pat. Nos. 12 46 404, German Offenlegungsschrift Nos. 15 22 dyes which have been found suitable:

Dye A is obtained as follows: 17.3 g of 2-amino-8 hydroxy-naphthalene-6 sulfonic acid are dissolved in 300 ml of water with the-addition of aqueous sodium hydroxide to produce a neutral sobaths, the dye thus being fixed lution. A'solution of gof sodium nitrite in ml of water and 100 g of ice are added, and into the mixture is poured all at once 20ml of concentrated hydrochloric acid with rapid stirring. Stirring is continued for minutes and the excess nitrous acid is destroyed and the diazo suspension is run into 120 g of a 16.6 percent aqueous NflzCOa/SOlLltlOfl within 5 minutes. The precipitated dye is removed by suction filtration after one hours stirring and washed with 2.5 percent sodium chloride solution. The residue is stirred into acetone to which 10 percent of water has been added, and it is then isolated by suction filtration, washed with acetone and dried. 16 g of dye are obtained. Dyes B and C may be obtained by similar methods.

Any gelatin layers used in photographic materials can be marked by means of the process according to the invention. The marks can be produced on the gelatin layer by means of a temporary carrier, for example by writing, e.g., using a felt tip impregnated with the dye solution, or by stamping with a rubber stamp or by printing through a typing ribbon or printing cloth impregnated. with the dye solution. The dye solutions rapidly penetrate the gelatin layers and. produce marks which cannot be wiped off and which are resistant to the usual photographic processing baths such as developer, fixing, stabilizing, hardening, silver bleaching or dye bleaching baths. The water-soluble dye solvents are removed from the gelatin in the aqueous photographic even more firmly in the gelatin layer.

The process according to the invention may be used, e.g., for making so-called cut marks-on the upper surface of photographic materials, such as may be required for automatically cutting up roll material. The process according to the invention is, however, preferably used for marking the rear surfacev of photographic materials whichhave a gelatin layer on the rear surface. These rear gelatin layers as already mentioned above, counteract the tendency of photographic materials to curl especially those materials in which the support consists of a synthetic resin'foil or a paper which has been coated with synthetic resin. It is more particularly in cases where automatic photographic processes are employed that marks in the form of figures are generally applied to the rear surfaces .of the pictures, these figures serving to identify thepictures or to give information about details of processing, for example in connection with color filtration in the case of color photographs.

A gelatin layer which contains additions of cellulose triacetate and wool fat has been found to be particularly suitable for taking up the dye solution according to the invention. The best results are obtained when the quantity ofcellulose triacetate is between 3 and 18 percent by weight and the quantity of wool fat between 1 and 6 percent by weight, based in each case on the dry weight of gelatin. In addition, the gelatin layer may contain matting agents such as barium sulfate, strontium sulfate, silicon dioxide or starch in the amounts v necessary for obtaining the desired effect. The amounts required can be determined by a few simple tests.

A gelatin layer containing cellulose triacetate and wool fat may be prepared, for example, from a precipitate of cellulose triacetate and wool fat which may be prepared according to the following method which is known per se;'this method may easily be varied according to the required particle size of the precipitate.

Wool fat Adeps Lanae DAB 6 (Deutsches Arzneibuch, 6th Edition) and cellulose triacetate are dissolved .in a suitable solvent mixture (e.g., toluene and ethyl alcohol) with stirring and heating to 40C, and an equal quantity of water is then added, cellulose triacetate and wool fat thus being precipitated in a finely granular form. The powder obtained may be isolated by suction filtration and added to the gelatin solution in this form, but alternatively the entire precipitate may be added to the gelatin without first being isolated by suction filtration.

The resulting gelatin layers have a slight to medium surface roughness, depending on the amount of cellulose triacetate and wool fat added, and this surface roughness may be increased bymeans of the matting agents mentioned above.

' The invention will now be further explained by means of examples.

EXAMPLE 1 I excess solution is then stripped off with a wiper. A ribbon suitable for marking gelatin layers is obtained after one hours drying in air.

A similar procedure is used for the other solvents mentioned or mixtures of these solvents and other dyes or dye mixtures.

To test the resistance of the solvent to evaporation, a piece of ribbon prepared according to Example 1 is stored ina drying cupboard at 45C for 48 hours. Its ability to produce marks when stamped is completely preserved. When compound 1 in Example l is replaced by formamide, ethylene glycol monoethyl ether, diacetone alcohol or 2-furaldehyde, the ribbon is completely dry after only 8 hours storage at 45C.

EXAMPLE 2 A gelatin layer applied to a pigmented Cellite foil is stamped in a stamping apparatus, using a conventional typewriter ribbon. Even after one hour the marking is not resistant to wiping, and after passing through a conventional photographic processing installation comprising developer, short stop, bleaching and fixing baths, the stamped marks have completely disappeared.

EXAMPLE 3 EXAMPLE 4 A precipitated mixture of cellulose triacetate and wool fat containing 12 percent by weight of cellulose triacetate and 4 percent by weight of wool fat, based in both cases on the dry weight of gelatin, was added to a percent aqeous gelatin solution which was then cast on a film support of cellulose triacetate (application approximately 10 u). The resulting gelatin layer was marked by means of a ribbon prepared according to Example 1. The marks were resistant to wiping after 1 minute, and both after passing through a conventional photographic processing installation and after passing through the usual baths used for the silver dye bleaching process they were found to have a greater depth of color than the marks obtained in Example 3.

EXAMPLE 5 Five percent of a mixture of barium sulfate and strontium sulfate, based on the dry weight of gelatin, are

added to a gelatin solution to which a mixture of cellugelatin layer is marked with the ribbon prepared as in Example 1, the same results as in Example 4 are obtained.

We claim:

1. in a process for applying a plurality of dye markings to a gelatin layer in a non-curling photographic material wherein the photographic material containing the gelatin layer is photochemically processed subsequent to the marking, the method of transferring a marking solution to an absorbing surface of a gelatin layer comprised of a material which resists curling of the photographic material in a manner that the solution rapidly penetrates the gelatin layer which comprises impregnating a woven ribbon carrier with a solution consisting essentially of a dye non-diffusing in gelatin in a water-soluble, non-drying low molecular weight solvent which is liquid at room temperature and a molecular weight below 300 and having the following formula:

Bl-OH H-C-N wherein R a straight chain or branched chain lower alkylene radical containing up to six carbon atoms;

R a hydrogen atom, a straight chain or'branched chain lower alkyl radical containing up to four carbon atoms, a straight chain or branched chain hydroxyalkyl radical containing up to six carbon atoms orv a straight chain or branched chain formylaminoalkyl radical containing up to six carbon atoms;

and contacting at about room temperature the carrier containing the dye and solvent in a quantitative ratio of several times more solvent than dye against the surface of the gelatin layer to transfer an amount of the solution sufficient to penetrate into the layer.

2. A process according to claim 1, characterised in that the gelatin layer'which is to be marked is situated on the rear surface of the photographic materials.

3. A process according to claim 1, characterised in that the gelatin layer which is to be marked in addition contains matting agents.

4. A process according to claim 3, characterised in that the gelatin layer which is to be marked contains 3 to 18 percent by weight of cellulose triacetate and l to 6 percent by weight of wool fat, based on the dry weight of the gelatin.

5. A process according to claim 1, characterised in that the dye solution is applied to the gelatin layer on an impression means which is wetted or impregnated with this solution thereby causing the solution to be delivered to the gelatin layer.

'UUINITED STATES PATENT OFFICE. CERTIFICATE OF CORRECTION Patent No 3 14 l- Dated June 11 197 lnvencor(s ma 'Vetter a 1-. a].

It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 6, the formula ofelam 1 should be a RI'OH 'n-c -n Signed and sealed this 14th day of January 1975.

(SEAL) Attest:

McCOY msoNf-JR, c. MA SH LL DANN Attesting Officer commlssloner of Patents Patent No I 33 v UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTIQN Dated June 11, 197 4 Inventor(s) Hans Vetter 8t 81 It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 3, formula A, the left hand ring should be Column 3, formula B, the left hand ring should be Signed and sealed this 26th day of November 19.74. I

(SEAL) Attest:

McCOY M. GIBSON JR. Attest ing 0f f icer C. MARSHALL DANN Commissioner of Patents FORM PO-IOSO (10-69) 

2. A process according to claim 1, characterised in that the gelatin layer which is to be marked is situated on the rear surface of the photographic materials.
 3. A process according to claim 1, characterised in that the gelatin layer which is to be marked in addition contains matting agents.
 4. A process according to claim 3, characterised in that the gelatin layer which is to be marked contains 3 to 18 percent by weight of cellulose triacetate and 1 to 6 percent by weight of wool fat, based on the dry weight of the gelatin.
 5. A process according to claim 1, characterised in that the dye solution is applied to the gelatin layer on an impression means which is wetted or impregnated with this solution thereby causing the solution to be delivered to the gelatin layer. 